Guard for rotary knives.



- No. 872,889. PATENTED DEC. s; 1907.

- B. E. BEGHTEL & J. BALL.

GUARD FOR ROTARY KNIVES. APPLIoATIoN FILED nn0.11,19os,

2 SHEETSLSHEET 1;

- W Witness I I g M M; I

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No. 872,889. PATENTED DEC. 3, 1907. B. B. BEGH-TEL & J. VBALL. GUARD FORROTARY KNIVES.

APPLIOATION TILED DEO.11,1906.

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THE NORRIS PETERS co., WASHINGTON, n. c.

UNITED STATES PATENT OFFICE.

BYRON EBB BEOHTEL AND JACOB BALL, OF WATERLOO, ONTARIO, CANADA.

GUARD FOR ROTARY'KNIVES.

Specification of Letters Patent.

Patented Dec. 3, 1907.

Application filed December 11. 1906. Serial No. 347.358.

To all whom it may concern:

Be it known that we, BYRON ERB BECHTEL and JACOB BALL, subjects of theKing of Great Britain, residing at Waterloo, Province of Ontario,Dominion of Canada, have invented certain new and useful Improvements inGuards for Rotary Knives and the Like; and we do hereby declare thefollowing to be a full, clear, and exact description of the invention,such as will enable others skilled in the art to which it appertains tomake and use the same.

I This invention relates to certain improvements in guards for rotarycutter heads; and more particularly relates to guards for rotary planerknives, and the like; and the objects and natureof our invention will bereadily understood by those skilled in the art in the light of thefollowing explanation of the construction shown in the accompanyingdrawings as the preferred embodiment from among other forms andarrangements within the spirit and scope of our invention.

An object of the invention is to provide an improved guard for rotarycutter heads which shall be quick in action with a minimum essentialrange of movement, and wherein a series of guard fingers will beemployed which can be arranged closely together to attain the maximumguarding efficiency without necessitating weakening of the planer bedplate or table to form slots for the reception of said fingers.

A further object of the invention is to provide a guard for rotaryplaner knives or heads wherein a series of parallel closely arrangedcurved pivoted fingers is employed, each finger approximately in theform of a semicircle and arranged almost concentric with the axis ofrotation of the planer or cutter head, and swinging on an axis arrangedparallel with and closely below the cutter head axis, whereby thefingers can be applied without weakening the planer bed plate or tableand have a short range of movement in uncovering and covering the planerknives or cutter head.

A further object of the invention is to provide an improved rotarycutter head guard comprising a series of curved parallel swingingfingers carried by and pivotally joined to the casting connecting thecutter head journal boxes.

A further object of the invention is to provide an improved rotarycutter head guard employing a series of swinging curved parallel fingersnormally and yieldingly held over and guarding the cutter head andbridging the opening therefor in the planer bed plate or table, wherebythe piece of wood advancing to the cutter head will engage the freeendsof the guards and cause withdrawal thereof below the top surface of saidbed plate; and to provide means whereby the force or power impellingsaid fingers to return to guarding position can be varied or reduced toml, and whereby when said force is reduced to nil, said fingers will bygravity drop to uncover'the cutter head.

A further object of the invention is to provide certain improvements indetails of con struction and arrangements whereby a highly eflicient andcomparatively simple and durable rotary cutter head guard Will beproduced.

The invention consists in certain novel features in construction andarrangements and combinations of parts as more fully and particularlyset forth and pointed out hereinafter.

Referring to the accompanying drawings:Figure 1, is a side elevationshowing portions of the frame, bed plate, cutter head, and guard of aplaning machine, dotted lines indicating certain hidden parts. Fig. 2,is a detail longitudinal section, on an enlarged scale, of the bar orframe carrying the cutter head shaft journal boxes, and the guardfingers. Fig. 3, is a detail cross section through the cutter head,guard and bed. Fig. 4, is a top plan of a portion of the planer bed,showing the guard in normal position, dotted lines indicating certainhidden parts.

In the drawings, 1, is the bed plate or table of a planing machine, orthe like, car ried by the frame or uprights 2, and having the transverseopening 3, in which the blades or knives 41, of the rotary cutter orplaner head 5, operate and through which they project to engage the workon the bed plate.

In the specific example illustrated, the planer knives'are arrangedlongitudinally of and secured in any approved manner to the head orstock 5, carried by the horizontal shaft 6, rotated in any suitablemanner and arranged transversely of the bed plate and below the openingor slot 3. The shaft 6, is, at its ends, mounted in usually separablejournal boxes 7, carried by the frame sides or uprights 2, and the lowerhalves or sections of the two journal boxes are usually at the ends of asingle casting or said lower journal,

box sections are rigidly connected by an elongated casting, metal bar orframe 8, arranged beneath and parallel with the planer head. Thiscasting or bar 8, arranged longitudinally of and beneath the planerhead, is spaced such a distance from the planer head that the planerknives will move above the top face of the bar with ample clearance, yetthe bar is preferably arranged as close to the planer head as possible.The bar 8, is usually concavo-convex or crescent shaped in cross sectionwith the transversely convexed bottom face. The bar is formed with alon- 'gitudinal series of alined perforated ears 9, arranged at theunder face thereof about in the vertical plane of the axis of the planerhead. The lower perforated ends of the spaced parallel curved guardfingers 10, overlap these ears 9, and the fingers are supported andpivotally joined to said ears by the horizontal transverse pivot bolt orrod 11, extending through the ears and finger ends and forming the axison which the fingers can independently swing.

Each finger 10, is usually crescent shaped or about semi-circular inform and if so desired, can taper in thickness from its lower andpivoted end to the upper and free end, and said fingers are usuallysimilar and closely arranged to form a series in length approximatelyequal to the length of the plan-er knives. We usually space the guardfingers about an eighth or quarter of an inch apart, more or less, toprevent the operators fingers passing between the guard fingers into thepath of the planer knives. Each finger, from its pivotal point, curvesrearwardly and upwardly along the convexed lower face of the bar 8, andfrom thence curves upwardly in rear ofthe planer head and forwardlyacross the beveled edge of the bed plate forming the rear wall of theslot or opening 3, and forwardly across said slot, with its free frontend dropping on or arranged above the face of' the bed plate just inadvance of the opening 3. The fingers above the rear top edge of the bar8 approximately follow the curvature of the circular path of movement ofthe planer knives, but with a curvature of a greater radius than that ofsaid circular path, so that the fingers are arranged outside ofsaidcircular path and hence out of contact with said knives.

If so desired, separating or spacing fins or flanges 12, can be providedbetween the fingers, and projecting rearwardly from the beveled bedplate edge forming the front wall of the opening or slot 3.

As so far described, the fingers would by gravity passrearwardly fromthe opening 3, and drop below the bed plate, and hence it is necessaryto provide means to yieldingly and normally hold the fingers in theirelevated operative guarding position bridging the opening 3, and closingthe same over the planer head. As an example of means which can beconveniently and efficiently employed for this purpose, 'I show thelower end of each finger, in advance of the axis on which it swings,formed or provided with a rigid depending arm 13, connected by a coiledspring 14, with an arm or pin 15, rigid with and projecting up from atransverse rock shaft 16, mounted in the frame sides or uprights andrigid with a rearwardly extending lever or handle 17. Each guard fingerhas a separate expansion spring connection 14, with the rock shaft 16,either through a pin or crank arm 15, one for each spring, or else allthe springs 14, can be connected to a uni versal bar 18, secured to andparallel with the rock shaft by a pair of the arms or pins 15, rigidwith the universal bar and shaft. It is obvious, that when the shaft 16,is rocked to distend the springs 14 that the guard fingers will bethereby forced and held to their limits of upward movement in guardingposition with their upper ends projecting over the bed plate in advanceof the planer head.

In the specific arrangement shown, the hand lever 17, extends to anaccessible point on the planing machine, and the spring tension isapplied to the guard fingers to yieldingly hold them in guardingposition by swinging said lever downwardly and catching the same under aholding or locking pin or catch 19, a vertical series of such pins 19,being usually arranged on the side of the frame so as to hold the leverin various positions to apply greater or less tension to the guardfingers, or to hold the lever in an elevated position with the springs14, in con tracted or inactive position. lever is thus elevated, so thatthe guard finers are relieved of the spring tension, said ngers will bygravity, drop back below the bed plate and thus expose the slot 3, andthe planer head to permit access to the planer head for adjustment ofthe knives, or for other purposes. The guards can then be quickly andeasily restored to guarding position, by simply depressing the-leverand, locking the same at the position where the springs will bedistended to apply the desired tension to the fingers to cause thedesired quick return thereof, on being pressed back and released. Inoperation, the piece of wood to be planed is moved toward the bed platetoward the planing head and engages the front free ends of all orcertain of the guard fingers and forces the fingers back to expose theWood to the action of the planer knives. When the piece of wood passesrearwardly beyond the points or ends of the fingers depressed, saidfingers very quickly fly back to guarding position.

By reason of the formation of the fingers and the manner of mounting thesame, and also by reason of the springs employed, the fingers move aminimum distance to uncover When the i the planing head and consequentlyhave but I circular a short return stroke to again cover said head andare very quick in action reducing to the minimum liability of accidentalengagement of the planing knives with the hands or fingers of theoperators.

It is evident that various changes and .modifications might be resortedto in the forms, constructions and arrangements of the parts describedwithout departing from the spirit and scope of this invention, hence wedo not wish to limit ourselves to the exact construction shown.

What we claim and desire to secure by Letters Patent is 1. Incombination, a bed having a cutter head opening, a rotary cutter headoperating through said opening, a bar arranged longitudinally beneathand carrying said cutter head, said bar beneath the head beingtransversely convexed at its ries of swinging parallel crescent shapedguard fingers carried by said bar and at their lower ends pivoted on acommon axial line at the under side of said bar, said fingers adapted toextend forwardly and upwardly along said convexed surface of said barand upwardly therefrom through and bridging said opening, said convexedsurface limiting the upward swing of said fingers, said fingers normallytending by gravity to swing down from said opening, and a manuallycontrolled spring device-yieldingly holding said fingers in operativeposition up against said convex surface and bridging said opening.

2. In combination, a bed having a cutter head opening, a rotary cutterhead working through said opening, a removable cutter head carrying bararranged longitudinally of and below said cutter head and provided withthe cutter head journal boxes, and a guard for said cutter headcomprising swinging fingers pivoted to and carried by said bar andextending upwardly therefrom and adapted to bridge said opening, andmeans normally and yieldingly holding said fingers in operative positionbridging said opening.

3. In combination, a bed having a cutter head opening, a rotary cutterhead arranged below said bed and adapted to work through said opening, amovable cutter head carrying bar arranged longitudinally of and closelybelow said head and provided with and carrying end journal boxes for thecutter head axis, and a cutter head guard comprising a series ofswinging spring held crescent shaped fingers carried by said bar and attheir lower ends arranged at the under side of the bar and pivotallyjoined thereto to swing on a common axial line.

4:. A rotary cutter head guard comprising a support arranged closelybelow and longitudinally of the cutter head, a series of closelyarranged crescent shaped swinging guard fingers extending partiallyaround the under surface, a sepath of movement of said head, saidfingers at their lower ends pivotally joined to said support to swing ona common axis, whereby said fingers tend under gravity to swing downfrom operative position, a spring tension device applied to each fingerto yieldingly hold the same up to operative position, and manuallycontrolled means for simultaneously varying or relieving the tension ofsaid device on'said fingers, whereby when said tension is relieved saidfingers automatically drop from operative position.

5. A rotary cutter head guard comprising a series of movable guardfingers adapted to extend partially around the path of movement of saidhead, each finger having a retractive coiled tension spring connectedthereto, and manually controlled means for simultaneously varying thetension of all of said springs, and of relieving all of said fingersfrom the tension of said springs to permit said fingers to drop bygravity from guarding position. 6. A rotary cutter head guard comprisinga series of swinging guard fingers adapted to extend partially aroundsaid cutter head and normally tending to drop by'gravity from operativeposition when released from the spring pressure, each finger having alateral arm, a rocking member, means for rocking said member and forholding the same in different positions, and retractive tension springsbetween said member and said arms and yieldingly holding the fingers upto operative position when said member is held in certain positions, andto relieve said fingers of the spring tension when said member is heldin other positions.

7. In combination, a bed plate having an opening therethrough, arotarycutter head working through said opening, journal boxes for the axis ofsaid head, a movable cross bar between and rigidly connecting saidjournal boxes, a series of swinging curved spring impelled guard fingersprojecting beneath and pivoted to said bar and adapted to extend uptherefrom to bridge said opening and cover said head.

8. In combination, a bed having an opening, a rotary cutter head workingthrough said opening, a removable bar arranged longitudinally of andbeneath said head and at its ends provided with the journal boxes forsaid head,'and a series of spring impelled curved swinging guard fingersextending beneath and engaging the under face of said bar and pivotallyjoined thereto and adapted to extend upwardly therefrom to bridge saidopening and cover said head.

9. In combination, a bed having an opening, a rotary cutter head workingthrough said opening, a bar arranged longitudinally of and beneath saidhead and formed with a series of alined ears, a series of swinging guardfingers pivotally joined to said ears different positions to vary orrelieve the tension of said springs on said fingers.

a bed 10. In combination, side frames, having a cutter head opening, arotary cutter head arranged transversely of the bed and frames andhaving end journals, a cutterheadcarrying movable cross bar arrangedbeneath said cutter head and carried by said side frames, said journalsbeing mounted on the ends of said bar, a vertically movable cutter headguard mounted on and carried by said bar and adapted to extendyieldingly up therefrom to bridge said opening and cover said head, andmeans yieldingly holding said guard in operative guarding positionsubstantially as described.

v11. In combination, a bed having a cutter head opening, a rotary cutterhead rotatable through and across said opening, a cross bar arrangedlongitudinally of and closely below said head, a vertically swingingcrescent shaped cutter head guard extending transversely of the underside of said bar and at its lower end pivotally joined to said bar at apoint intermediate the width of said bar, said erases bar having aportion to one side of said pivoted end of said guard forming a stopadapted to engage said guard and limit the upward swing thereof, saidguard adapted to extend upwardly from said bar to bridge said openingand cover said head, and a spring device normally yieldingly holdingsaid guard in operative guarding position.

12. In combination, a rotary cutter head, a support arrangedlongitudinally thereof and adjacent thereto, a crescent shaped cutterhead guard at its lower end swingingon said support and carried thereby,said guard adapted to partially surround the path of movement of saidhead to guard the same, said head adjacent to its lower end having adepending arm, a retractive spring attached to said arm to yieldinglyhold the guard to operative position, and a movable support connected tothe opposite end of said spring, whereby the tension of the spring onthe guard can be varied, or can be relieved to permit the guard to dropfrom operative position.

In testimony whereof we aifix our signae tures in presence of twowitnesses.

BYRON ERB BECHTEL. JACOB BALL. IVitnesses:

A. L. KUMPF, E. P. FLINTOFT.

